Regenerating oak (Quercus spp.) is a problem on most intermediate to high-quality sites throughout the eastern US. Oak is often present in the overstory and abundant in the understory, but is absent from the midstory due to increased competition from less-valuable mesic species such as Liriodendron tulipifera and Acer rubrum. Red maple has expanded its range dramatically since fire suppression began in the 1930s, and is an important competitor of oak. To study relationships between oak and silvicultural treatments, an experiment was initiated in 1990 that included three northern red oak (Quercus rubra)-dominated stands and three red pine (Pinus resinosa) plantations in northern Lower Michigan. Areas of each stand were thinned to four levels of canopy cover in 1991: clearcut, 25% residual canopy, 75% residual canopy, and uncut control, with caged and uncaged northern red oak seedlings planted within each treatment. A thick midstory of red maple developed over the subsequent ten years, hindering development of advance oak regeneration. Low-intensity, early-spring prescribed fires were conducted on all stands in 2002 and 2008 in an effort to control red maple. Heights of planted red oak and naturally occurring red maple and oak regeneration in three size classes were measured before and after each fire with the objectives to: 1) Test the hypothesis that oak sprouts would have greater height growth after the 2008 prescribed burn than after the 2002 prescribed burn; 2) Test the hypotheses that (a) red maple stems would be reduced to a greater degree following the 2008 burn than following the 2002 burn, and that (b) the number of natural oak stems would be increased to a greater degree following the 2008 burn than following the 2002 burn; and 3) Evaluate the relationships between post-burn planted oak sprout height and pre-burn planted oak sprout height, fire temperature, and canopy cover. Following the second fire, planted oak sprouts increased in height rapidly in pine stands, where there was little red maple competition, but grew less rapidly in oak stands. Red maple densities decreased more following the first fire than the second fire. The hypothesis that natural oak regeneration stem densities would increase to a greater degree following the 2008 burn than following the 2007 burn was not supported. Pre-burn planted oak height was the best predictor of post-burn planted oak height.

Below-ground effects during forest fires are some of the important issues forest managers consider when conducting prescribed fire programs. Heat transfer models in soil are needed to predict temperatures in soil during forest fires. Many of the heat transfer models in soil that include the effects of moisture are complex and in most cases do not have very good predictive abilities. Researchers believe that simple heat transfer models in soil that neglect the effects of moisture could have very good predictive abilities.<p>This study presents a one-dimensional numerical model of heat transfer in dry homogenous sand. Both constant and temperature dependent thermal properties of the sand were used in order to determine which had better predictive abilities. The constant thermal properties model was also extended to a model of two-layer dry soil. A computer code written in Fortran was used to generate results from the model. A number of experiments were conducted with dry sand to validate the model. A comparison of the numerical and experimental results indicated that the temperature dependent properties model had better predictive abilities than the constant properties model. The models were found to do a good job of predicting temperature profiles and depth of lethal heat penetration at heat fluxes indicative of forest fires.<p>Experiments were also conducted to determine the effect of moisture on temperature profiles and the depth of lethal heat penetration in sand and the effect of inorganics on the spread rate of smoldering combustion in peat moss. An experimental correlation of the effects of inorganic content on the spread rate of smoldering combustion in peat moss was developed. Additionally, laboratory methods of validating models of heat transfer in soil were developed with the aim of limiting the dependence on full scale testing. Specifically the use of the cone calorimeter for validating numerical models of heat transfer in soil and the responses of forest floor soil and laboratory created soil samples to heat input were compared. The results indicated that the laboratory created soil did a very good job of mimicking the heat response of the forest floor soil with a maximum difference in lethal heat penetration of 4%.

Below-ground effects during forest fires are some of the important issues forest managers consider when conducting prescribed fire programs. Heat transfer models in soil are needed to predict temperatures in soil during forest fires. Many of the heat transfer models in soil that include the effects of moisture are complex and in most cases do not have very good predictive abilities. Researchers believe that simple heat transfer models in soil that neglect the effects of moisture could have very good predictive abilities.<p>This study presents a one-dimensional numerical model of heat transfer in dry homogenous sand. Both constant and temperature dependent thermal properties of the sand were used in order to determine which had better predictive abilities. The constant thermal properties model was also extended to a model of two-layer dry soil. A computer code written in Fortran was used to generate results from the model. A number of experiments were conducted with dry sand to validate the model. A comparison of the numerical and experimental results indicated that the temperature dependent properties model had better predictive abilities than the constant properties model. The models were found to do a good job of predicting temperature profiles and depth of lethal heat penetration at heat fluxes indicative of forest fires.<p>Experiments were also conducted to determine the effect of moisture on temperature profiles and the depth of lethal heat penetration in sand and the effect of inorganics on the spread rate of smoldering combustion in peat moss. An experimental correlation of the effects of inorganic content on the spread rate of smoldering combustion in peat moss was developed. Additionally, laboratory methods of validating models of heat transfer in soil were developed with the aim of limiting the dependence on full scale testing. Specifically the use of the cone calorimeter for validating numerical models of heat transfer in soil and the responses of forest floor soil and laboratory created soil samples to heat input were compared. The results indicated that the laboratory created soil did a very good job of mimicking the heat response of the forest floor soil with a maximum difference in lethal heat penetration of 4%.

Regenerating oak (Quercus spp.) is a problem on most intermediate to high-quality sites throughout the eastern US. Oak is often present in the overstory and abundant in the understory, but is absent from the midstory due to increased competition from less-valuable mesic species such as Liriodendron tulipifera and Acer rubrum. Red maple has expanded its range dramatically since fire suppression began in the 1930s, and is an important competitor of oak. To study relationships between oak and silvicultural treatments, an experiment was initiated in 1990 that included three northern red oak (Quercus rubra)-dominated stands and three red pine (Pinus resinosa) plantations in northern Lower Michigan. Areas of each stand were thinned to four levels of canopy cover in 1991: clearcut, 25% residual canopy, 75% residual canopy, and uncut control, with caged and uncaged northern red oak seedlings planted within each treatment. A thick midstory of red maple developed over the subsequent ten years, hindering development of advance oak regeneration. Low-intensity, early-spring prescribed fires were conducted on all stands in 2002 and 2008 in an effort to control red maple. Heights of planted red oak and naturally occurring red maple and oak regeneration in three size classes were measured before and after each fire with the objectives to: 1) Test the hypothesis that oak sprouts would have greater height growth after the 2008 prescribed burn than after the 2002 prescribed burn; 2) Test the hypotheses that (a) red maple stems would be reduced to a greater degree following the 2008 burn than following the 2002 burn, and that (b) the number of natural oak stems would be increased to a greater degree following the 2008 burn than following the 2002 burn; and 3) Evaluate the relationships between post-burn planted oak sprout height and pre-burn planted oak sprout height, fire temperature, and canopy cover. Following the second fire, planted oak sprouts increased in height rapidly in pine stands, where there was little red maple competition, but grew less rapidly in oak stands. Red maple densities decreased more following the first fire than the second fire. The hypothesis that natural oak regeneration stem densities would increase to a greater degree following the 2008 burn than following the 2007 burn was not supported. Pre-burn planted oak height was the best predictor of post-burn planted oak height.

Grasslands are characterized by recurring disturbances such as fire and grazing occurring against a background of topoedaphic heterogeneity and climatic variability. The result is a complex, multi-scaled disturbance regime, in which fire and grazing often have interactive roles, yet they have usually been studied independently. Relationships between climate, fire and simulated grazing (=mowing) were explored to determine the roles these disturbances play in shaping patterns and processes in southern mixed-grass prairie. A field experiment investigated the potential effects of these disturbances on above and belowground plant productivity, patch dynamics, and soil respiration over a 2-year period characterized by drought (1998) and normal (1999) rainfall. Spring burning and mowing had interactive effects on aboveground net primary production (ANPP). Consistent with published single factor studies, burning without mowing doubled ANPP, whereas mowing in the absence of burning had neutral effects. However, subsequent mowing on burned plots reduced ANPP gains to levels comparable with all unburned plots. Drought reduced ANPP by 22% relative to a normal rainfall year. In contrast to the traditional model of root response to defoliation, burning and mowing each stimulated root length recruitment measured with minirhizotrons. However, subsequent mowing on burned plots did not produce additional root recruitment. Fire and mowing appear to interact by affecting different components of root recruitment (production and mortality, respectively). Root biomass recovered from ingrowth cores were not correlated with minirhizotron results, and responded only to drought, suggesting that methodological differences have contributed to the varied root responses reported in the literature. Drought suppressed soil respiration, diminished soil moisture, and enhanced soil temperature, whereas fire and/or mowing had little effect. Results suggest that any fire or mowing effects on soil respiration in southern mixed-grass prairie may be highly constrained by moisture limitations during dry periods. In summary, patch level response to fire is a pulse of root recruitment followed by increased ANPP, unless subsequent grazing offsets these gains. Grazing alone produces a pulse of root recruitment, perhaps to replace consumed foliage. This study demonstrates the interactive nature of fire and grazing in grasslands, and the perils of single-factor studies.

Tall fescue, a cool-season grass native to Europe, central Asia, and northern Africa, has been widely distributed throughout the U.S. for use as turf and forage. Following its widespread planting, its ability to associate with a toxic fungal endophyte, Neotyphodium coenophialum, was discovered. Research has linked this fescue-endophyte association with increased biotic and abiotic stress resistance in endophyte-infected (E+) versus endophyte-free (E-) plants, and these differences may affect the ability of land managers to eradicate tall fescue and restore native grasslands. I conducted three studies to examine whether E+ tall fescue plants respond differently to management than E- plants, and whether the success of planted native species might be impacted via indirect soil effects. My overall hypotheses were that E+ plants would recover from restoration/eradication efforts better than E- plants, and that E+ fescue would reduce microbial symbionts in the soil needed by planted native species. I first conducted a field study of a tall fescue pasture consisting of four sub-units being restored with different combinations of prescribed burns and/or herbicide applications, as well as an unmanaged control. I found no evidence of E+ plants preferentially surviving restoration management; however this field had unusually low endophyte infection rates to begin with. The second study was a greenhouse experiment in which I measured growth of E+ and E- plants exposed to different watering regimes (wet, dry) and prescribed burn treatments (none, one, or two burns). Watering regime significantly affected all measured growth parameters (wet>dry), but few endophyte effects were found and when present were opposite the hypothesis (E->E+). All burned plants quickly re-grew tiller lengths comparable to the unburned control, with recovery occurring faster following the second burn compared to the first. My final study examined growth and arbuscular mycorrhizal colonization of native species planted by seed into soil from beneath E+ and E- tall fescue. I observed few differences in mycorrhizal colonization or biomass for seedlings between soil from E+ and E- tall fescue. Taken together, my results indicate endophyte status of tall fescue pastures being restored to native grassland species may not be important in governing restoration success.

There is a critical need for more studies to identify socio-ecological drivers that affect conservation and management of fire adapted ecosystems, yet studies that identify such variables and explore their interaction in specific systems are not only scarce but limited to only a few systems. Although information on the socio-ecological effects of prescribed fire application exists, there is no integrative framework that simultaneously considers the interplay between social and ecological factors affecting the use of prescribed fires. Fire suppression, together with other human and natural disturbances in grassland systems that are adapted to episodic fire, are the major factors that have contributed to the recruitment of woody species into grasslands worldwide. Even though the ecology of restoring these fire prone systems back to a grassland state is becoming clearer, the major hurdle to reintroducing historic fire at a landscape scale is its social acceptability. To address these deficiencies, I studied the socio-ecological factors influencing the use of prescribed fire in Texas, USA and Chihuahua, Mexico using a combination of quantitative and qualitative approaches to examine how social and ecological factors affect ecosystem conservation and management of semi-arid grassland systems. For the Texas case study I used quantitative survey data analyzed using logistic regression models and structural equation models. For the Mexico case study I used qualitative interviews gathered using a snowball network sampling approach and coded them based on the analytic themes of land cover change, institutional failure, market drivers, and population dynamics. Results from the Texas case study suggest that risk taking orientation and especially, perceived support from others when implementing prescribed burns, play important roles in determining attitudes towards the use of high-intensity prescribed fires, which are sometimes needed to restore ecosystems. Results from the Texas case study also highlight how membership in Prescribed Burn Associations (PBAs) influence land manager decisions regarding the use of prescribed fire by reducing concerns over lack of skills, knowledge and resources. Results emphasize the potential for PBAs to reduce risk concerns regarding the application of prescribed fire and are relevant to management of brush encroached areas. Through PBAs, effective landscape-scale solutions to the brush encroachment problem can be achieved in Texas. Results from the Mexico case study show how fire stopped effectively being a driving factor on this system decades ago. Socio-political and ecological changes at the national, and international level produced changes in land use disrupting historical fire patterns and contributing to the ecological deterioration of the area. Droughts combined with poor management practices have depleted the fuel needed to carry a fire. Landowners also face safety and legal concerns but in most cases, even if a landowner decided to implement a prescribed burn, an ecological threshold has been crossed and current fine fuel loads (grass) are insufficient to carry a fire that is sufficiently intense to reduce brush cover and restore grassland and savanna ecosystems. Based on my findings I can conclude that ecologically sound adaptive management and social capital are fundamental components of the livelihoods of landowners and land managers in both case studies. Work and investment that is focused on strengthening this social capital will have the most profound effects in maintaining the integrity of grassland systems at a landscape scale.

Fire has influenced species composition within the Central Hardwood Forest for millennia. Since the last glacial retreat, Native Americans followed by European settlers used fire as a tool to manipulate their environment. This fire use by humans helped maintain the dominance of well-adapted oak-hickory species across eastern forests. By the 1940's, land fragmentation from increased settlement and actively enforced suppression policies effectively eliminated fire from the landscape. Without the disturbance of recurrent fire that alters succession, the fertile loess-capped hills of southern Illinois have undergone several decades of compositional and structural change manifested by encroachment of mixed mesophytic competitors that are maladapted to fire. Today, land managers seek practical methods to restore declining oak-hickory forests. Southern Illinois forests in particular are lacking information on how cutting and prescribed fire techniques can be applied to encourage regeneration of oak-hickory species. In 2002, five sites were chosen across the Greater Shawnee Hills geographic region for similar ecological characteristics. A factorial combination of thinning and a fire treatment consisting of two burns was used to test the response of understory components including: seedling density, seedling height, seedling diameter, non-tree cover and available sunlight. Results showed a distinct improvement in oak-hickory seedling competitive position as compared to non oak-hickory species. Seedlings of sassafras out-competed all other groups in this study and were the only species to increase in both density and height following repeated fire. The non-tree vegetation layer increased as a result of thin from below treatments, while burning had no effect on the amount of available sunlight. Generally, woody seedlings benefited from thinning based on their physiological adaptations and fire essentially acts as a filter selecting for traits of disturbance-prone vegetation.

Fire is a vital part of the taiga ecosystems and as the amount of prescribed fires increases, it is also likely that public awareness and interest in fire increases and thereby also the need for nature interpreters who can perform guided tours in these areas. This report aims to provide guidance for nature interpreters as to what information they should convey while guiding groups of people in taiga forests where fire has occurred. The methods used to study this were: 1) Interviews with conservationists who work with forest fire in some way on what information they think is important to convey and 2) a web survey in which respondents answered questions about their knowledge and feelings about forest fire. Based on the results of the interviews it is concluded that the focus of the guided tour should be on explaining fire as a natural phenomenon of the taiga and its role in the dynamics of the taiga. Based on the result of the web survey it is also concluded that the guide should bear in mind that though the participants of the tour may well be aware that fire is beneficial for the taiga they may not know how and why that is, nor what happens if the taiga does not burn, and some effort should thus be put into explaining those mechanisms. / Eld är en livsviktig del i taigans ekosystem och medan mängden genomförda naturvårdsbränder ökar är det också rimligt att tro att allmänhetens medvetenhet och intresse för brand ökar. Därigenom kan också behovet av guidade turer i brandområden öka. Målet med denna rapport är att ge vägledning till guider om vilken information som bör förmedlas under guidade turer i brandområden. Metoderna för att studera detta var: 1) intervjuer med naturvårdare som på något sätt jobbar med brand och 2) en webbenkät där respondenter svarar på frågor om deras kunskap om, och inställning till, brand. Baserat på resultaten från intervjuerna dras slutsatsen att fokus i de guidade turerna bör ligga på att förmedla att brand är ett naturligt fenomen och vilken roll branden har i taigans dynamik. Baserat på resultatet från webbenkäten dras också slutsatsen att även om deltagarna i turen mycket väl kan vara medvetna om brandens positiva effekter på skogen så vet de kanske inte varför och hur, eller vad som händer om taigan inte brinner. Därför bör kraft även läggas på att förklara dessa mekanismer.

Although prescribed burning has been used frequently for manipulating habitat, it has been rarely used in grassland areas with the intent to improve habitat quality for wild turkeys (Meleagris gallapavo). I studied breeding season and nest location habitat use of wild turkey hens in response to grassland fire management, and quantified its impact on foraging habitat and insect prey for turkey poults, in a diverse agricultural landscape in southern Illinois. Fire management was conducted on 28 ha of grassland in March and April 2012. Radiolocations from 64 radiomarked hens from 2008-2010 and 44 radiomarked hens from 2012-2013 were used to create turkey habitat and nest location models for both pre-fire and post-fire time periods. Areas used by turkeys throughout all models and time periods were characterized by high proportions of forested habitat. Nest locations during both time periods also included areas with higher percentages of shrubland and edge habitat. Turkey use areas during the post-fire time period were found to be further from burned areas, suggesting that fires on short rotations (1-2 years) were slightly detrimental to habitat needed during the breeding season and for nest locations. Field trials using human-imprinted wild (n=54) and commercial (n=64) strain turkey poults were conducted to assess the foraging efficiency and mobility of poult type within burned and unburned grassland sections. Foraging efficiency of turkey poults did not differ between burned or unburned fields, or between wild and commercial strain poults. All poults showed selection of invertebrate categories Coleoptera, Hymenoptera, and Isopoda throughout all grassland field trials, whereas avoidance of Araneae, Diptera, Entognatha, Hemiptera, Lepidoptera, and Orthoptera was exhibited by all poults in all trials. There was evidence to believe that burned grasslands increased the travel efficiency of poults compared to unburned grasslands. Wild poults were able to travel further distances and along less sinuous paths than commercial poults.